Twitter users provide tiny bursts of information about their activities by updating or “tweeting” their answer to the question, “What are you doing right now?” Tweets must be 140 characters or less.

But there is money to be made in mundane tweets.

Twitter doesn’t release the number of active accounts, but web traffic analysis site Compete.com reports that Twitter is now the third most popular social networking service after Facebook and Myspace. Six million people visited Twitter last February.

Rapidly growing social networking sites like Twitter and Facebook make advertisers salivate because of the wealth of personal data they accumulate.

Facebook is already making money by turning users’ profile information into a massive marketing survey and letting companies use it to create individually tailored ads.

With vast and growing armies of twitterers — and Twitter’s increasing importance as a professional networking tool — there is a concern about the transparency of what’s being peddled by sponsors rather than users.

Jessica Weber recently told her followers on Twitter about a sale at the Apple store.

“Apple has refurbished iTVs on sale,” the tweet read, complete with the punctuation lapses common to twitter users. “while supplies last . i got mine couple months ago. love it!!!”

Weber, a graphic designer from Victoria, B.C., doesn’t have an iTV.

In fact, she didn’t even write that message.

Magpie is not affiliated with Twitter. But Marshall Kirkpatrick, the head writer for the tech blog ReadWriteWeb, said the way Magpie is using the site to make money shows the potential for social media to take its business model in a disturbing direction.

Online ads are nothing new, but the difference is disclosure. There’s a “presumption of authentic voice” in Twitter messages, said Kirkpatrick.

The amount of money Magpie users can earn is based on how many followers they have and what they’re tweeting about.

In the six months Weber’s been using the service, she says she’s accumulated about $1.50 from corporate use of her name. Users have to make about $80 before they get paid.

Even though the likelihood of getting rich quick is low for the average Twitter user, Magpie is gaining popularity with both Twitter users and advertisers in Canada.

Jan Schulz-Hofen, the head of Magpie, told The Canadian Press there are more than 1,000 companies who use the service, and about 50 are Canadian. About 80,000 of the two million people who follow Magpie users on Twitter are Canadian, he said.